PPE protection levels overview

Level A protection should be used when the job requires the highest level of respiratory, skin, and eye protection. Under 1926.65 App B, examples include situations with high concentrations (or potential for high concentrations) of vapors, gases, or particulates, operations with a high potential for splash or immersion, substances known or suspected to be highly hazardous to the skin, or work in confined/poorly ventilated areas where conditions requiring Level A have not been ruled out.

• See the Level A hazard criteria in 1926.65 App B for specifics on when full encapsulation and positive-pressure respirators are indicated.

Level B protection is appropriate when the highest level of respiratory protection is needed but a lower level of skin protection is acceptable. 1926.65 App B explains that Level B applies where the atmosphere requires full-face, positive-pressure breathing protection (e.g., IDLH or unknown high inhalation hazard), but substances present do not pose a severe skin absorption or contact hazard.

• The appendix also notes Level B is required if the atmosphere contains less than 19.5% oxygen or if direct-reading instruments indicate vapors/gases but severe skin hazards are not suspected.

Level C protection is correct when the contaminants and concentrations are known, and an air-purifying respirator (APR) can adequately remove the contaminants. 1926.65 App B states Level C is used when air contaminants will not adversely affect or be absorbed through exposed skin, concentrations are measured and within APR limits, and all criteria for air-purifying respirator use are met.

• Level C commonly uses full-face or half-mask APRs with appropriate cartridges/filters, plus chemical-resistant clothing as listed in the appendix.

Level D protection is acceptable when the atmosphere contains no known hazard and work functions preclude splashes, immersion, or unexpected inhalation or contact with hazardous chemical levels. 1926.65 App B describes Level D as a minimal protection work uniform for nuisance contamination only (coveralls, safety glasses, etc.).

• Use Level D only after hazard assessment shows no airborne contaminants, no potential for skin absorption, and no other physical or chemical hazards that require higher protection.

The main difference is that Level A provides the highest skin, eye, and respiratory protection, while Level B provides the highest respiratory protection but less skin protection. 1926.65 App B lists Level A equipment such as totally-encapsulating chemical-protective suits with positive-pressure SCBA or supplied air, whereas Level B focuses on positive-pressure respirators with hooded chemical-resistant clothing rather than full encapsulation.

• Choose Level A when skin exposure risk is high or unknown; choose Level B when inhalation risk is primary but skin risk is lower.

Level A PPE in 1926.65 App B includes positive-pressure, full face-piece SCBA or positive-pressure supplied-air respirator with escape SCBA; totally-encapsulating chemical-protective suit; coveralls and long underwear (as applicable); inner and outer chemical-resistant gloves; chemical-resistant boots with steel toe and shank; and a hard hat worn under the suit (as applicable).

• The appendix lists other optional items (e.g., disposable protective suit components) and emphasizes that materials’ performance against the specific hazard must be considered.

Level B PPE in 1926.65 App B includes positive-pressure, full-facepiece SCBA or positive-pressure supplied-air respirator with escape SCBA; hooded chemical-resistant clothing (overalls, jackets, splash suits); inner and outer chemical-resistant gloves; chemical-resistant boots (outer) with steel toe and shank; disposable chemical-resistant boot covers; hard hat (as applicable); and optionally a face shield.

• Level B focuses on providing maximum respiratory protection while using chemical-resistant clothing that is not totally encapsulating.

Level C PPE in 1926.65 App B includes full-face or half-mask air-purifying respirators (NIOSH-approved), hooded chemical-resistant clothing, coveralls, chemical-resistant outer and inner gloves, chemical-resistant boots with steel toe and shank, disposable outer boot-covers, hard hat, escape mask, and face shield.

• Level C requires that the contaminants be identified and concentrations measured so that an APR can adequately protect the worker; otherwise a higher level of respiratory protection is required.

Level D PPE in 1926.65 App B includes basic work uniforms such as coveralls, gloves, steel-toe chemical-resistant boots or shoes, disposable outer chemical-resistant boots, safety glasses or chemical splash goggles, hard hat, escape mask, and face shield as needed.

• Level D is for nuisance contamination only and does not provide respiratory or significant skin protection.

An employer should ensure the chosen PPE material’s breakthrough time exceeds the expected work duration or layer PPE so that exposure does not reach the skin through the material. 1926.65 App B explains that many protective materials vary by chemical and that when continuous protection cannot be guaranteed, the material’s breakthrough time should be longer than the worker’s expected exposure time.

• Consider task duration, potential for repeated exposures, and use of multiple layers or protective overgarments to extend overall protection.

Yes — 1926.65 App B explicitly states that combinations of PPE selected from different levels may be more suitable and can be used to match site hazards and tasks. The appendix cautions that the listed combinations are guidelines and employers must evaluate PPE performance for the specific chemical hazards present.

• Any combination should be based on a hazard assessment and may be adjusted as more site information becomes available.

PPE selection should account for the effects of heat stress and how long workers will wear protective gear, balancing protection against the risk of heat-related illness. 1926.65 App B notes that the physiological effects of PPE (e.g., heat retention) and the duration of tasks are key factors in selecting and using PPE, and that layers or alternate protection strategies may be needed.

• Employers should monitor workers for heat stress, schedule breaks, provide hydration, and consider less heat-retaining protection if compatible with hazard control.

Material durability and seam strength must be considered so PPE can withstand the employee's actual tasks without failure. 1926.65 App B emphasizes evaluating tear strength, seam integrity, and overall durability in relation to the task to ensure the PPE maintains its barrier properties during use.

• Employers should match PPE materials to task hazards and replace or upgrade PPE if durability does not meet job demands.

Yes — employers must assess the workplace to determine PPE needs and provide a written certification when PPE is required. OSHA's interpretation on PPE hazard assessment clarifies that employers must perform a workplace hazard assessment and document it when PPE is necessary, as part of the employer's responsibility to protect workers; see OSHA's PPE hazard assessment letter of interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-03-28 and review PPE selection guidance in 1926.65 App B.

• The assessment should identify chemical, biological, physical hazards, and routes of exposure and be updated as conditions change.

Employers should use NFPA suit performance standards when appropriate because 1926.65 App B recommends chemical protective suits that meet NFPA 1991, 1992, or 1993 for vapor-protective or liquid splash protection. The appendix states these NFPA standards include labeling and performance requirements and recommends selecting suits compliant with the appropriate NFPA standard.

• Use NFPA-labeled suits when those performance criteria match the site hazards (vapor vs liquid splash vs non-emergency situations).

For Class I asbestos work, employers must follow the asbestos standard's respirator requirements: use full facepiece supplied-air respirators (SARs) in pressure-demand mode with an auxiliary positive-pressure SCBA when exposures exceed 1 f/cc TWA; at or below 1 f/cc TWA provide full facepiece SARs or tight-fitting PAPRs unless a negative exposure assessment allows selection under Table 1 of 29 CFR 1910.134. See OSHA's asbestos respirator interpretation at https://www.osha.gov/laws-regs/standardinterpretations/2024-01-04 and consult 1926.65 App B for PPE-level guidance.

• Do not substitute less protective respirators if the asbestos standard requires higher protection based on measured exposures.

If site information is incomplete, employers should err on the side of higher protection and re-evaluate as more information becomes available, upgrading or downgrading PPE to match known hazards. 1926.65 App B advises that when site conditions are not fully known, combinations of PPE or higher protection levels may be appropriate and PPE selection is an ongoing process.

• Conduct initial monitoring, limit worker exposure, and document reassessments as conditions and data develop.

Escape masks are included as optional items in Levels C and D and should be available for emergency egress when needed. 1926.65 App B lists an escape mask among Level C and D equipment, indicating its use for emergency escape from contaminated atmospheres or if expeditious egress becomes necessary.

• Employers should ensure escape masks are NIOSH-approved and workers are trained in their use.

Yes — disposable protective suits, gloves, and boots may be worn over totally-encapsulating suits when appropriate, depending on suit construction and task conditions. 1926.65 App B mentions that disposable components may be worn over encapsulating suits to provide added protection or to protect expensive inner suits.

• Use disposable outer layers when contamination removal is needed to reduce inner suit cleaning or to extend usable service in high-contamination tasks.

Employers should use Level B protection (or higher) when the atmosphere is oxygen-deficient (less than 19.5% oxygen), because positive-pressure supplied-air respirators or SCBA are required rather than air-purifying respirators. 1926.65 App B explicitly lists atmospheres below 19.5% oxygen as a situation requiring Level B respiratory protection.

• Always measure oxygen levels in confined or poorly ventilated spaces and select respirators that provide breathable air independent of the ambient atmosphere.

Employers should continuously re-evaluate PPE selection as more hazard information becomes available and when tasks, conditions, or monitoring results change. 1926.65 App B stresses that PPE selection, evaluation, and re-selection is an ongoing process until sufficient information about hazards and PPE performance is obtained.

• Reassessment triggers include new sampling data, changes in work task, observed PPE failures, or worker health complaints.